Hello,
I have a question about redistribution of BGP into IGP (P.42&43 of bgpSols.pdf). "Only routes learnt by E-BGP are redistributed into IGP." I am wondering what is the correct meaning of this sentence. Does it mean that:
1. every route learnt from E-BGP will be redistrbuted into IGP
2. or only the best route (of a border BGP router) learnt from E-BGP will be redistrbuted into IGP?
According to the example of P.43, the route leant by R6 from R5 is redistributed into IGP after being advertised via I-BGP and E-BGP. It seems my first understanding is correct.
However, there is a question, Question 5 of Problem 2, about this topic from final 2021(Exam2021.pdf). The answer says "the prefix 2614 : 9fca : 1f7c :: /48 is redistributed into OSPF by V4 and V2 with distance 21." If the first understanding is correct, then there should be routes reidistributed by V3 and V5 because they also have routes leant by E-BGP from R3 and R4. The only possible explanation is that the best routes of V3 and V5 are learnt by I-BGP (shortest AS-PATH) and they are not redistributed into IGP, which means the second understanding is correct.
Could you explain which one is correct and why the answer didn't mention V3 and V5?
Best,
Xianjie
